Fluoroalkoxyphenyl-substituted nitrogen heterocycles as plant stunting agents

ABSTRACT

There is disclosed a class of fluoroalkoxyphenyl-substituted nitrogen-containing heterocycles which are useful as herbicides, plant fungicides, and plant growth regulators. Internodal elongation of plants is inhibited by treatment with compounds of this invention.

BACKGROUND OF THE INVENTION

Methods and substances useful for the control of the height of plantshave been the subject of much research for many years. Such control isof great economic benefit in many instances.

In the prior art, Margot et al., U.S. Pat. No. 2,839,446 (June 17,1958), teach novel pyrimidines which are said to possess fungicidalactivity. The Margot et al. compounds are distinguished by having atleast one trichloromethane sulphenylmercapto group preferably attachedat the 2-position of the pyrimidine ring.

In addition, Ballard et al., U.S. Pat. No. 2,658,895 (Nov. 10, 1958),teach 2-alkylphenyl-3,4,5,6-tetrahydropyrimidines, which are alleged tohave fungicidal and detergent properties, and also are alleged to haveuse as asphalt additives.

Schellenberger et al., Angew. Chem. 76 (5), 226-7 (1964), teach the useof 2-methyl-5-hydroxymethylpyrimidine as an intermediate in thesynthesis of a cocarboxylase inhibitor. This pyrimidine compound has theR¹ and R² substituents equal to hydrogen in the generic formula shownbelow, and, in our tests, has been found to be inactive both as a plantfungicide and as a plant growth regulator.

Bredereck et al., Chem. Ber., 93, 230-35 (1960), teach the preparationof 5-isopropylpyrimidine and 5-isoheptylpyrimidine, respectively. Noutility is disclosed therefor.

Lewin et al., Arch. Biochem. and Biophysics, 101, 197-203 (1963), teachthe use of 5-hydroxymethylpyrimidine as a substrate in studying the invivo inhibition of thiamine synthesis.

Belgian Patent No. 714,003 (Oct. 22, 1968), teaches a series of5-pyrimidinemethanols as being useful as plant fungicides and growthregulators.

Also in the prior art, Behun et al., Jour. Org. Chem., 26, 3379 (1961),teach the synthesis of 2-diphenylmethylpyrazine; however, there is noteaching of utility for the compound.

Klein et al., Jour. Org. Chem., 29 2623 (1964), teach only the method ofsynthesis of 2-ethoxy-3-pyrazinemethanol. No utility is alleged for thecompound.

Rutner et al., Jour. Org. Chem., 28, 1898 (1963), teach the preparationof pyrazylmethanol, but not utility is alleged therefor.

Akkerman et al., Netherlands No. 105,432 (July 15, 1963), teach thepreparation of α,α-diphenyl-2-pyrazineacetonitrile andα,α-diphenyl-2-pyrazineacetamide, which compounds are alleged to possesssedative and anticonvulsant properties.

Taylor et al., U.S. Pat. No. 3,544,682 (Dec. 1, 1970) teach the use ofsubstituted pyrazines to control plant pathogenic fungi.

Hirschberg et al., Jour. Heterocyclic Chem., 2, 209 (1965), teach thepreparation of 2-(3,6-dimethylpyrazinyl)-phenylcarbinol and homologues.However, no utility for the compounds is taught.

Additionally in the prior art, Sperber et al., U.S. Pat. No. 2,727,895(Dec. 20, 1955), teach that certain 4-substituted pyridines, and thepiperidines produced therefrom by hydrogenation of the pyridine ring,are useful primarily as anticonvulsants, and secondarily, asantibacterials and amtifungals, when administered in a variety of theusual pharmaceutical forms, such as tablets, elixirs, solutions andcapsules. Thus, the Sperber et al. compounds are directed toward use inanimals or humans.

Another prior art reference is Hoffmann et al., U.S. Pat. No. 3,153,046(Oct. 13, 1964), which teaches dialkylpiperidylmethanols as havingfungicidal, and especially antibacterial, properties useful againstMicrosporum audouini, Trichophyton interdigitalis, and Staphylococcusaureus, and against tubercle bacilli. Hoffmann et al. teach that theircompounds can be used as disinfectants, preservatives, or as medicamentsfor the treatment of bacterial infections, and thus the compounds areimplicitly directed to use in humans or animals.

Duerr et al., U.S. Pat. No. 3,203,855 (Aug. 31, 1965), teach a methodfor combatting phytopathogenic organisms, i.e., fungi or bacteria, usingthe compound 2-(2,2,2-trichloro-1-hydroxyethylamino)pyridine, whichcompound differs significantly from those described in the instantapplication.

Also in the prior art is Van Heyningen, U.S. Pat. No. 3,396,224 (Aug. 6,1968), which teaches that substituted 3-pyridylmethane derivatives areactive against phytopathogenic fungi. The compounds disclosed by VanHeyningen have shown most activity against airborne fungi, little or noactivity against soil-borne fungi, and minimal activity as plant growthregulators.

SUMMARY

The present invention relates to a class of novelfluoroalkoxyphenyl-substituted nitrogen-containing heterocycles. Thesenovel compounds have been found effective as plant growth regulators.Internodal elongation of crop plants, ornamental plants, woody plantsand turf is inhibited by treatment with these novel compounds at a rateof about 0.125 to about 5 lbs./A. Such treatment does not injure theplants.

DESCRIPTION OF THE PREFERRED EMBODIMENT

It is an object of this invention to provide novelfluoroalkoxyphenyl-substituted nitrogen-containing heterocycliccompounds, as well as methods for the use of and compositions containingsuch compounds, which methods and compositions are useful for regulatingthe growth of crop plants, ornamental plants, woody plants, and turf.

In fulfillment of this object, this invention provides novel compoundsof the class represented by the formula ##EQU1## wherein R is2-pyrazinyl, 3-pyridyl, or 5-pyrimidinyl;

R¹ is phenyl, pyridyl, C₁ -C₁₂ alkyl, or C₃ -C₈ cycloalkyl;

R² is trifluoromethoxyphenyl, tetrafluoroethoxyphenyl,pentafluoroethoxyphenyl, 3,4-(difluoromethylenedioxy)phenyl, or2,2,4,4-tetrafluoro-1,3-benzodioxanyl;

X is hydrogen, hydroxy, lower alkoxy, lower alkylthio, or loweralkanoyloxy; and

the nonphytotoxic acid addition salts thereof.

In the above formula I, C₁ -C₁₂ alkyl can be any branched or straightchain saturated hydrocarbon radical, such as methyl, ethyl, n-propyl,isopropyl, n-butyl, isobutyl, sec.-butyl, tert.-butyl, n-amyl, isoamyl,sec.-amyl, tert.-amyl, n-hexyl, isohexyl, sec.-hexyl, n-heptyl,isoheptyl, sec.-heptyl, n-octyl, isooctyl, sec.-octyl, n-nonyl,isononyl, n-decyl, isodecyl, n-undecyl, isoundecyl, n-dodecyl,isododecyl, and the like.

Pyridyl for R¹ refers to 2-pyridyl, 3-pyridyl, and 4-pyridyl.

C₃ -C₈ cycloalkyl refers to a monocyclic, saturated hydrocarbon radical,and includes cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl,cycloheptyl, and cyclooctyl.

Lower alkoxy refers to C₁ -C₄ alkoxy and includes methoxy, ethoxy,n-propoxy, isopropoxy, n-butoxy, sec.-butoxy, isobutoxy, and t-butoxy.

Lower alkylthio refers to C₁ -C₄ alkylthio and includes methylthio,ethylthio, n-propylthio, isopropylthio, n-butylthio, sec.-butylthio,t-butylthio and isobutylthio.

Lower alkanoyloxy refers to C₂ -C₅ alkanoyloxy and includes acetyloxy,propionyloxy, butyryloxy, and valeryloxy.

While the novel compounds of the present invention have been defined interms of a structural formula which depicts the structural features ofthe compounds used, and which indicates the presence therein of certainwell-known organic radicals, including alkyl, cycloalkyl, pyridyl,pyrimidyl, pyrazinyl, and phenyl, it will be recognized by those skilledin the art that such radicals may bear one or more substituents withoutdeparting in any way from the spirit of the invention and withoutaltering the properties of the compounds in such a way as would set themapart from the invention or take them outside its scope. Compoundshaving the structure depicted by the generic formula, supra, and bearingsuch substituents are accordingly considered as equivalents of theunsubstituted compounds. Among such substituent atoms and radicals arehalo, hydroxy, nitro, lower alkyl, trifluoromethyl, methoxy,methylmercapto, cyano, hydroxymethyl, β-hydroxyethyl, acetyl, acetamido,and the like. It is to be fully understood that all compounds comingwithin the scope of the generic formula I, supra, contain afluoroalkoxyphenyl moiety, represented by R², supra.

Suitable nonphytotoxic acid addition salts of those compounds comingwithin the scope of the generic formula, supra, and sufficiently basicto allow formation of such salts, can be prepared, employing, forexample, the following acids: hydrochloric, hydrobromic, sulfuric,phosphoric, nitric, oxalic, p-toluenesulfonic, benzenesulfonic,methanesulfonic, maleic and the like. It will be understood by thoseskilled in the art that suitable salts include those which are notsubstantially more phytotoxic than the free bases from which they arederived.

Compounds coming within the scope of the generic formula, supra,include, but are not limited to the following:

α-Methyl-α-[p-(trifluoromethoxy)phenyl]-5-pyrimidinemethanol

α-Ethyl-α-[p-(pentafluoroethoxy)phenyl]-5-pyrimidinemethanol

α-Methyl-α-[p-(trifluoromethoxy)phenyl]-2-pyrazinemethanol

α-Ethyl-α-[p-(pentafluoroethoxy)phenyl]-2-pyrazinemethanol

α-[p-(Pentafluoroethoxy)phenyl]-α-(n-propyl)-3-pyridinemethanolhydrochloride

α-[3,4-(Difluoromethylenedioxy)phenyl]-α-(n-heptyl)-5-pyrimidinemethanol

α-(n-Octyl)-α -[p-(1,1,2,2-tetrafluoroethoxy)phenyl]-3-pyridinemethanolhydrobromide

α-Isobutyl-α-[p-(1,1,2,2-tetrafluoroethoxy)phenyl]-2-pyrazinemethanolsulfate

α-Isopropyl-α-(2,2,4,4-tetrafluoro-1,3-benzodioxan-6-yl)-5-pyrimidinemethanol

α-(n-Pentyl)-α-[p-(trifluoromethoxy)phenyl]-2-pyrazinemethanol

α-(n-Nonyl)-α-[p-(trifluoromethoxy)phenyl]-5-pyrimidinemethanolmethanesulfonate

α-(n-Dodecyl)-α-[p-(1,1,2,2-tetrafluoroethoxy)-phenyl]-3-pyridinemethanoloxalate

α-(n-Decyl)-α-[p-(trifluoromethoxy)phenyl]-5-pyrimidinemethanol

α-Cyclopropyl-α-[p-(1,1,2,2-tetrafluoroethoxy)phenyl]-3-pyridinemethanol

α-Cyclobutyl-α-[p-(trifluoromethoxy)phenyl]-2-pyrazinemethanol

α-Cyclopentyl-α-[p-(pentafluoroethoxy)phenyl]-5-pyrimidinemethanol

α-(p-Tolyl)-α-[p-(trifluoromethoxy)phenyl]-3-pyridinemethanol

α-(Valeryloxy)-α-(sec.-butyl)-α-[p-(1,1,2,2-tetrafluoroethoxy)phenyl]-5-methylpyrimidine

α-(α,α,α,-Trifluoro-m-tolyl)-α-[p-(trifluoromethoxy)-phenyl]-2-pyrazinemethanol

α-Cyclooctyl-α-[p-(pentafluoroethoxy)phenyl]-2-pyrazinemethanol

α-(p-Tolyl)-α-[p-(trifluoromethoxy)phenyl]-3-pyridylmethane

α-(α,α,α-Trifluoro-m-tolyl)-α-[p-(trifluoromethoxy)-phenyl]-2-pyrazinylmethane

α-(n-Pentyl)-α-[p-(1,1,2,2-tetrafluoroethoxy)phenyl]-3-pyrimidylmethane

α-Ethyl-α-[p-(pentafluoroethoxy)phenyl]-5-pyrimidylmethane

α-(p-Bromophenyl)-α-[p-(trifluoromethoxy)phenyl]-3-pyridinemethanol

α-[3,4-Difluoromethylenedioxy)phenyl]-α-(m-fluorophenyl)-5-pyrimidinemethanol

α-(o-Chlorophenyl)-α-[p-(pentafluoroethoxy)-phenyl]-2-pyrazinemethanol

α-(3-Pyridyl)-α-[p-(trifluoromethoxy)phenyl]-3-pyridinemethanol

α-Cyclobutyl-α-methoxy-α-[p-(trifluoromethoxy)phenyl]-2-methylpyrazine

α-(Ethylthio)-α-(n-hexyl)-α-[p-(pentafluoroethoxy)-phenyl]-3-methylpyridine

α-(Acetyloxy)-α-(n-propyl)-α-[p-(1,1,2,2-tetrafluoroethoxy)phenyl]-5-methylpyrimidine,and the like.

The novel nitrogen-containing heterocyclic compounds of this inventionare prepared utilizing halo-substituted nitrogen-containing heterocyclesas key starting materials. These particularly preferred startingmaterials are 5-bromopyrimidine, 2-iodopyrazine, and 3-bromopyridine.All of these compounds are compounds known to those skilled in the art,and the preparations thereof have been described in the literature.These particular halo compounds are preferred because of their readyavailability and their excellent reactivity in the condensationreactions.

Both the novel pyrimidine and the pyrazine compounds useful in the novelmethods and compositions of this invention can be synthesized byproceeding in general according to the preparative method taught inBelgian Patent No. 714,003. Following that method, in general, asuitable ketone, for example, isopropyl p-trifluoromethoxyphenyl ketoneand 5-bromopyrimidine, or 2-iodopyrazine, are dissolved in a solventcomposed of equal volumes of tetrahydrofuran and ethyl ether. Thesolution is cooled to -70° C., and while being maintained at thattemperature, a solution of n-butyllithium in n-hexane is added. Thereaction mixture is stirred overnight in the cold (-60° to -70° C.) Thereaction product mixture is then worked up. It is washed successivelywith dilute aqueous ammonium chloride solution and water, and theorganic layer is separated and dried over a suitable drying agent. Thedried organic layer is concentrated to dryness in vacuo and the residueis chromatographed on a silica column using acetone-benzene diluent. Thedesired product is eluted from the column using a suitable eluent, forexample, one composed of 10 percent acetone and 90 percent benzene byvolume. The eluate, which contains the product, is concentrated invacuo. The product, a heavy oil, is identified by elemental analyses,NMR, and IR spectra, asα-isopropyl-α-[p-(trifluoromethoxy)phenyl]-5-pyrimidinemethanol, orα-isopropyl-α-[p-(trifluoromethoxy)phenyl]-2-pyrazinemethanol, dependingon the starting nitrogen heterocycle.

The preparation of the substituted 3-pyridine compounds is carried outin a slightly different manner. A solvent composed of equal volumes oftetrahydrofuran and ethyl ether is cooled to a temperature of about -30°to -40° C., the n-hexane solution of n-butyllithium is added thereto,and the whole cooled to a temperature of about -70° C. The3-bromopyridine is dissolved in a suitable solvent, preferably anhydrousethyl ether, and this ether solution is added dropwise to thetetrahydrofuran-ether solution of the n-butyllithium, while maintainingthe temperature at about -70° C. A suitable ketone, for example,isopropyl p-trifluoromethoxyphenyl ketone, dissolved in anhydroustetrahydrofuran-ethyl ether mixture (1:1), is then added to the reactionmixture. The remainder of the preparation and work-up proceeds asdescribed supra, for the pyrimidine and pyrazine compounds. In thepresent instance, the product obtained is identified asα-isopropyl-α-[p-(trifluoromethoxy)phenyl]-3-pyridinemethanol, byelemental analyses and NMR spectrum.

Those compounds in the above generic formula I where X is C₁ -C₄ alkoxycan be prepared by allowing an alkali-metal lower alkoxide such assodium methoxide, potassium ethoxide, sodium propoxide, potassiumbutoxide, sodium butoxide, or the like, to react in the correspondingalkanol as solvent with a halo analogue of the desired product, forexample,5-[α-chloro-α-cyclohexyl-3,4-(difluoromethylenedioxy)benzyl]pyrimidine(prepared according to the procedure outlined in Belgian Patent No.714,003), to yield the desired product,α-loweralkoxy-α-cyclohexyl-α-[3,4-(difluoromethylenedioxy)phenyl]-5-pyrimidylmethane.

Those compounds where X is C₁ -C₄ alkylthio can be prepared by allowinga suitable C₁ -C₄ alkyl mercaptan to react with a halo analogue of thedesired product, for example2-[α-chloro-α-isopropyl-p-(trifluoromethoxy)benzyl]pyrazine (preparedaccording to the procedure set forth by Taylor et al., U.S. Pat. No.3,544,682 (Dec. 1, 1970)), in the presence of triethylamine, to yieldthe desired C₁ -C₄ alkylthio substituted product,α-loweralkylthio-α-isopropyl-α-[p-(trifluoromethoxy)phenyl]-2-pyrazylmethane.

In the case where X is C₁ -C₄ alkanoyloxy, the compound can be preparedby allowing a mixture of the halo analogue of the desired product, forexample, 3-[α-chloro-α-isopropyl-p-(trifluoromethoxy)benzyl]pyridine(prepared according to the procedure set forth in Van Heyningen, U.S.Pat. No. 3,396,224 (Aug. 6, 1968)), with glacial acetic acid, forexample, in the presence of anhydrous sodium acetate, to yield thedesired product,α-loweralkanoyloxy-α-isopropyl-α-[p-(trifluoromethoxy)phenyl]-3-pyridylmethane.It will be obvious to one skilled in the art that other organic acids ororganic acid anhydrides may be used for preparation of these alkanoyloxyderivatives of the methanol compounds.

When X is H in the generic formula I, supra, the compounds can beprepared according to the procedure of Sperber et al., U.S. Pat. No.2,727,895 Dec. 20, 1955), whereby the 5-substituted pyrimidinemethanol,2-substituted pyrazinemethanol, or 3-substituted pyridinemethanol(prepared as set forth above) is heated in a mixture of glacial aceticacid and 47 percent aqueous hydriodic acid to reduce the hydroxy groupand yield, respectively, the 5-substituted pyrimidinemethane,2-substituted pyrazinemethane, or 3-substituted pyridinemethane.

The nonphytotoxic acid addition salts of the above-prepared compoundsare readily prepared, by methods well known to the art, from those novelcompounds which are sufficiently basic. Thus, the free base is dissolvedin ether, the solution cooled and saturated with, for example, anhydroushydrogen chloride gas. The hydrochloric acid addition salt of thesubstituted compound precipitates and is filtered off and purified byrecrystallization.

The ketone intermediates used in the preparation of the above-describednovel compounds of this invention are themselves novel compounds of theformula ##EQU2## wherein R¹ and R² are identified in the same manner asset forth hereinabove for formula I.

The preparations of these novel ketones are accomplished according to anumber of procedures appearing in the prior art. Thus, the preparationof isopropyl p-trifluoromethoxyphenyl ketone is carried out by heprocedure of Sheppard, Jour. Org. Chem. 29, 1 (1964 ). Following thesame general procedure, other related ketones are readily prepared.

The preparation of ketones containing the3,4-(difluoromethylenedioxy)phenyl moiety is accomplished by firstsynthesizing 3,4-(difluoromethylenedioxy)bromobenzene according to theprocedure of Stogryn, Jour. Org. Chem. 37, 673, (1972). This substitutedbromobenzene is then allowed to react with an aldehyde, for example,isobutyraldehyde, in the presence of n-butyllithium, at about -40° C.,to yield the intermediate alcohol, isopropyl3,4-(difluoromethylenedioxy)phenyl carbinol. This alcohol is oxidizedusing chromium trioxide in aqueous acetic acid to yield isopropyl 3,4-(difluoromethylenedioxy)phenyl ketone. Additional3,4-(difluoromethylenedioxy)phenyl substituted ketones, alkyl or aryl,can be prepared in the same general manner.

The preparation of pentafluoroethoxy-substituted phenyl alkyl ketones isaccomplished following the procedure of Belous et al., J. Org. Chem.(U.S.S.R.) 7, 1521 (1971). According to that procedure p-bromophenol isallowed to react with trifluoroacetic anhydride in the presence ofsulfur tetrafluoride and hydogen fluoride, to yieldpentafluoroethoxy-4-bromobenzene. This compound is allowed to react withisobutyraldehyde in the presence of n-butyllithium to yield theintermediate alcohol, isopropyl p-(pentafluoroethoxy)phenyl carbinol.This alcohol is oxidized with chromium trioxide in the presence ofaqueous acetic acid to yield the ketone, isopropylp-(pentafluoroethoxy)phenyl ketone.

The compound, 1,1,2,2-tetrafluoroethoxy-4-bromobenzene, is commerciallyavailable. It is used to prepare a Grignard reagent, which is in turnallowed to react with isobutyronitrile to yield one of the desiredketones, isopropyl p-(1,1,2,2-tetrafluoroethoxy)phenyl ketone. Otherp-(1,1,2,2-tetrafluoroethoxy)phenyl substituted alkyl or aryl ketonesare prepared in the same general manner.

For the preparation of a ketone such as isopropyl2,2,4,4-tetrafluoro-1,3-benzodioxan-6-yl ketone, the procedure disclosedin U.S. Pat. No. 3,632,820 (Jan. 4, 1972), Example 6, is used to preparethe intermediate halobenzodioxane. According to that reference,fluoroformic acid 2-trichloromethyl-4-chlorophenyl ester is allowed toreact with anhydrous hydrofluoric acid to yield2,2,4,4-tetrafluoro-6-chloro-1,3-benzodioxane. This compound can then beutilized to prepare the isopropyl2,2,4,4-tetrafluoro-1,3-benzodioxan-6-yl or related alkyl or arylketones by any of the methods set forth above for the other ketones.

The syntheses of these novel intermediate ketones are set forthhereinbelow.

PREPARATION 1 Isopropyl p-trifluoromethoxyphenyl ketone

Using about 800 ml. of anhydrous tetrahydrofuran as solvent, theGrignard reagent was prepared from 50 g. of p-bromophenyltrifluoromethylether and 5.5 g. of magnesium turnings. To the Grignard reagent thusprepared, 15 g. of isobutyronitrile was added slowly, dropwise. Theaddition of the nitrile required about one-half hour. The reactionmixture was heated to refluxing for about 10 hours, cooled, anddecomposed by the addition of aqueous 1N hydrochloric acid withstirring, to a pH of approximately 3.The aqueous layer was separatedfrom the organic layer and the aqueous layer was discarded. The organiclayer was dried over anhydrous magnesium sulfate. The drying agent wasthen filtered off and the filtrate was concentrated in vacuo. Theresidue was distilled to yield a liquid product having a boiling pointof about 97°-98° C., at house vacuum pressure. The product weighed 19 g.It was identified by infrared spectrum as isopropylp-trifluoromethoxyphenyl ketone.

PREPARATION 2 Isopropyl p-pentafluoroethoxyphenyl ketone

Starting with 4-bromophenol, the preparation of4-bromopentafluoroethoxybenzene was carried out following the procedureof Belous et al., J. Org. Chem. (U.S.S.R.) 7, 1521 (1971).

To a solution of 15 g. of the thus prepared4-bromopentafluoroethoxybenzene in 200 ml. of anhydrous ethyl ether, wasadded 25 ml. of a 22 percent solution of n-butyllithium in n-hexane. Themixture was cooled to about -60° C., and while being maintained at thistemperature, to the mixture was added slowly a solution of 10 g. ofisobutyraldehyde in 200 ml. of anhydrous ethyl ether. The reactionmixture was maintained at about -60° C., and stirred overnight, followedby stirring for a period of 48 hours at room temperature.

The reaction product mixture was worked up by the addition of aqueousammonium chloride solution. The organic phase was separated and driedover anhydrous magnesium sulfate. The drying agent was filtered off. Thefiltrate was concentrated in vacuo to yield product having a weight ofabout 23 g. The product was identified by infrared spectrum as isopropylp-pentafluoroethoxyphenyl carbinol.

The carbinol thus prepared, 20 g., was dispersed in 200 ml. of glacialacetic acid with stirring, and to the mixture was added 20 g. ofchromium trioxide dissolved in 30 ml. of water. The addition was carriedout carefully and the reaction temperature was kept below 80°C. Stirringof the mixture was continued for 4 hours. The reaction product mixturewas cooled and poured onto a mixture of crushed ice and aqueous 50percent sodium hydroxide solution, and the pH adjusted to pH 8. Themixture was extracted with large volumes of ether, and the etherextracts combined and washed with dilute aqueous sodium hydroxidesolution. The ether solution was dried and concentrated in vacuo. Theresidue was chromatographed over a silica column using benzene assolvent and eluent, to yield 7 g. of product which was identified by NMRand infrared spectra as isopropyl p-pentafluoroethoxyphenyl ketone.

PREPARATION 3 3,4-(Difluoromethylenedioxy)phenyl isopropyl ketone

A mixture of 50 g. of 3,4-(methylenedioxy)bromobenzene and 200 g. ofphosphorus pentachloride was heated at about 80°C. for about 4 hours. Atthe end of this time, the reaction product mixture was distilled and thematerial boiling at 115°-125°C. was collected. It weighed about 42 g.and was identified by NMR spectrum as3,4-(dichloromethylenedioxy)bromobenzene.

A mixture of 3,4-(dichloromethylenedioxy)bromobenzene, 42 g., and 28 g.of antimony trifluoride was heated under reduced pressure. Atapproximately 80°-82°C., the product distilled over, and there wascollected 34 g. of product identified by elemental analyses as3,4-(difluoromethylenedioxy)bromobenzene.

To 56 g. of 3,4-(difluoromethylenedioxy)bromobenzene in 250 ml. oftetrahydrofuran was added 110 ml. of a 22 percent solution ofn-butyllithium in n-hexane at -70°C., in an atmosphere of nitrogen. Tothis mixture was added 16 g. of isobutyraldehyde, and the reactionmixture was stirred overnight at about -70°C. The reaction productmixture was worked up by pouring it into a concentrated aqueous ammoniumchloride solution with stirring. The organic layer was separated anddried. The drying agent was filtered off and and the organic solventremoved in vacuo. A total of 27 g. of the crude carbinol,3,4-(difluoromethylenedioxy)phenyl isopropyl carbinol, was obtained andused without further purification in the next step.

Following the same general procedure as described in Preparation 2, thecarbinol, 27 g., was oxidized with chromium trioxide in glacial aceticacid, to yield 3,4-(difluoromethylenedioxy)phenyl isopropyl ketone,weighing 16 g. and identified by NMR spectrum.

PREPARATION 4 Cyclohexyl 3,4-(difluoromethylenedioxy)phenyl ketone

To a solution of 24 g. of 3,4-(difluoromethylenedioxy)bromobenzene in250 ml. of ether was added 2.4 g. of magnesium shavings. To the Grignardreagent thus prepared was added 11 g. of cyclohexylcarboxaldehyde in 50ml. of anhydrous ethyl ether. The reaction mixture was allowed to stirfor about 2-3 hours. The reaction product mixture was worked up byadding to it at room temperature a concentrated aqueous solution ofammonium chloride. The organic layer was separated, dried, filtered fromthe drying agent, and concentrated in vacuo. The residue, which is thecrude carbinol, was oxidized with chromium trioxide and glacial aceticacid. The oxidation was worked up by pouring onto a mixture of crushedice and 50 percent aqueous sodium hydroxide. The mixture was extractedwith ethyl ether. The ether solution was dried, the drying agentfiltered off, and the filtrate concentrated in vacuo. The residue thusobtained was dissolved in benzene and chromatographed over a silicacolumn using benzene as the eluent. There was obtained 8 g. ofcyclohexyl 3,4-(difluoromethylenedioxy)phenyl ketone, identified by itsinfrared and NMR spectra.

Following the same general procedure set forth above and using suitablestarting materials, additional ketones were prepared:

3,4-(Difluoromethylenedioxy)phenyl undecyl ketone. Melting point: oil.Identified by infrared spectrum.

3-Chloro-4'-tetrafluoroethoxybenzophenone. Melting point: oil.Identified by infrared spectrum.

3-Pyridyl p-tetrafluoroethoxyphenyl ketone. Melting point: oil.Identified by infrared spectrum.

The following examples describe in detail the methods used in preparingthe novel substituted nitrogencontaining heterocyclic compounds of thisinvention. However, the invention is not be construed as limitedthereby, either in spirit or in scope, since it will be apparent tothose skilled in the art that many modifications both of materials andmethods may be practiced within the purpose and intent of thisdisclosure.

EXAMPLE 1α-Isopropyl-α-[p-(trifluoromethoxy)phenyl]-5-pyrimidinemethanol

To a solution of 19 g. (0.082 mole) of isopropylp-trifluoromethoxyphenyl ketone, in 250 ml. of a mixture of equalvolumes of tetrahydrofuran and ethyl ether was added a solution of 32 g.(0.1 mole) of 5-bromopyrimidine in 350 ml. of tetrahydrofuran-ethylether, and the mixture was cooled to -70°C., in an atmosphere of drynitrogen gas. The mixture was stirred and maintained at about -70°C., inthe atmosphere of dry nitrogen gas, while there was added 60 ml. of a 15percent solution of n-butyllithium in n-hexane. The resulting reactionmixture was maintained at about -70°C., with stirring for a period ofabout 8 hours.

The reaction product mixture was allowed to warm to room temperature.Aqueous ammonium chloride solution was added, and the aqueous andorganic layers were separated. The organic layer was washed with waterand dried over anhydrous magnesium sulfate. The drying agent wasfiltered off and the filtrate was concentrated in vacuo to yield an oilweighing about 33 g. This oil was chromatographed on a silica column,and the desired product was eluted from the column using a solventmixture of 10 percent acetone and 90 percent benzene by volume. Theacetone-benzene eluate was concentrated in vacuo, to yield a heavy oilweighing about 14 g. This heavy oil was identified by NMR and infraredspectra, and elemental analyses, asα-isopropyl-α-[p-(trifluoromethoxy)phenyl]-5-pyrimidinemethanol.

Following the same general procedure set forth hereinabove, and usingsuitable starting materials, the following additional compounds weresynthesized:

α-Isopropyl-α-[p-(1,1,2,2-tetrafluoroethoxy)phenyl]-5-pyrimidinemethanol.Melting point: dark

α-Cyclohexyl-α-[p-(1,1,2,2-tetrafluoroethoxy)phenyl]-5-pyrimidinemethanol.Melting point: oil. Structure identified by NMR spectrum.

α-n-Hexyl-α-[p-(1,1,2,2-tetrafluoroethoxy)phenyl]-5-pyrimidinemethanol.Melting point: oil. Structure identified by NMR spectrum.

α-(m-Chlorophenyl)-α-[p-(1,1,2,2-tetrafluoroethoxy)phenyl]-5-pyrimidinemethanol.Melting point: oil. Structure identified by NMR spectrum.

EXAMPLE 2α-Cyclohexyl-α-[3,4-(difluoromethylenedioxy)phenyl]-5-pyrimidinemethanol

To a solution of 8 g. of cyclohexyl 3,4-(difluoromethylenedioxy)phenylketone, in 125 ml. of a mixture of equal volumes of tetrahydrofuran andethyl ether, was added a solution of 4.7 g. of 5-bromopyrimidine in 50ml. of tetrahydrofuran-ethyl ether, and the mixture was cooled to-70°C., in an atmosphere of dry nitrogen gas. The mixture was stirredand maintained at about -70°C., in the atmosphere of dry nitrogen gas,while there was added 13 ml. of a 15 percent solution of n-butyllithiumin n-hexane. The resulting reaction mixture was maintained at -70°C.,while being stirred for a period of about 8 hours.

The reaction product mixture was allowed to warm to room temperature.Aqueous ammonium chloride solution was added and the aqueous organiclayers were separated. The organic layer was washed with water and driedover anhydrous magnesium sulfate. The drying agent was filtered off andthe filtrate was concentrated to yield a crude product having a weightof about 7 g. This crude product was chromatographed on a silica column,and the desired product was eluted from the column using a solventmixture of 10 percent acetone and 90 percent benzene by volume. Theeluate was concentrated in vacuo and the residue became a solid glass,having a melting point of about 64°C. It was identified by NMR spectrumasα-cyclohexyl-α-[3,4-(difluoromethylenedioxy)phenyl]-5-pyrimidinemethanol.

Following the same general procedure set forth above and using suitablestarting materials, the following additional compounds were prepared:

α-[3,4-(Difluoromethylenedioxy)phenyl]-α-isopropyl-5-pyrimidinemethanol.Melting point: 127°C. Structure confirmed by NMR spectrum and elementalanalyses.

α-[3,4-(Difluoromethylenedioxy)phenyl]-α-undecyl-5-pyrimidinemethanol.Melting point: oil. Structure identified by NMR spectrum.

EXAMPLE 3 α-Isopropyl-α-[p-(trifluoromethoxy)phenyl]-2-pyrazinemethanol

To a solution of 9 g. of isopropyl p-trifluoromethoxyphenyl ketone in300 ml. of ethyl ether, was added a solution of 10 g. of 2-iodopyrazinein 300 ml. of ethyl ether, and the mixture was cooled to a -70°C., in anatmosphere of dry nitrogen gas. The mixture was stirred and maintainedat about -70°C., in the atmosphere of dry nitrogen gas, while there wasadded 25 ml. of a 15 percent solution of n-butyllithium in n-hexane. Theresulting reaction mixture was maintained at -70°C., while being stirredovernight.

The reaction product mixture was allowed to warm to room temperature.Aqueous ammonium chloride solution was added and the aqueous and organiclayers were separated. The organic layer was washed with water and driedover anhydrous magnesium sulfate. The drying agent was filtered off andthe filtrate was concentrated to yield an oil. This oil waschromatographed on a silica column, and the desired product was elutedfrom the column using a solvent mixture of 5 percent acetone and 95percent benzene by volume. The acetone-benzene eluate was concentratedin vacuo, to yield a heavy oil which upon standing solidified. The solidhad a melting point of about 70°C., and was identified by NMR spectrumand elemental analyses asα-isopropyl-α-[p-(trifluoromethoxy)phenyl]-2-pyrazinemethanol.

Following the same general procedure set forth hereinabove and usingsuitable starting materials, the following additional compounds weresynthesized:

α-(3-Pyridyl)-α-[p-(1,1,2,2-tetrafluoroethoxy)phenyl]-2-pyrazinemethanol.Melting point: oil. Structure identified by NMR spectrum.

α-Isopropyl-α-[p-(1,1,2,2-tetrafluoroethoxy)phenyl]-2-pyrazinemethanol.Melting point: oil. Structure identified by NMR spectrum.

EXAMPLE 4 α-Isopropyl-α-[p-(trifluoromethoxy)phenyl]-3-pyridinemethanol

To a solution of 250 ml. of a mixture of equal volumes oftetrahydrofuran and ethyl ether, cooled to about -30° to about -40°C.,and maintained under an atmosphere of dry nitrogen gas, was added 50 ml.of a 15 percent solution of n-butyllithium in n-hexane. The mixture wasstirred and cooled to about -70°C, and there was added thereto asolution of 16 g. of 3-bromopyridine in 250 ml. of the 50:50 by volumemixture of tetrahydrofuran and ethyl ether. After the addition wascomplete, the reaction mixture was allowed to stir for about one-halfhour. A solution of 20 g. of isopropyl p-trifluoromethoxyphenyl ketonein 100 ml. of the mixture of tetrahydrofuran and ethyl ether was thenadded dropwise with stirring. The resulting reaction mixture wasmaintained at -70°C. while being stirred overnight.

The reaction product mixture was allowed to warm to room temperature,and aqueous ammonium chloride solution was added. The aqueous andorganic layers were separated. The organic layer was washed with waterand dried over anhydrous magnesium sulfate. The drying agent wasfiltered off and the filtrate was concentrated to yield a yellow oilhaving a weight of about 43 g. This oil was chromatographed on a silicacolumn, and the desired product was eluted from the column using asolvent mixture of 10 percent acetone and 90 percent benzene by volume.The acetone-benzene eluate was concentrated in vacuo, to yield a yellowoil weighing about 11 g. On standing, the oil solidified. The solid wasrecrystallized from hot ether to yield white crystals having a meltingpoint of about 81°-82°C. The crystalline product was identified by NMRspectra asα-isopropyl-α-[p-(trifluoromethoxy)phenyl]-3-pyridinemethanol.

Following the same general procedure set forth hereinabove and usingsuitable starting materials, the following compound was synthesized:

α-Cyclohexyl-α-[p-(1,1,2,2-tetrafluoroethoxy)phenyl]-3-pyridinemethanol.Melting point: oil. Structure identified by NMR spectrum.

These novel fluoroalkoxyphenyl-substituted nitrogen heterocycles areactive as herbicides, plant fungicides, and as plant growth regulators.Thus, it has been found that, for example, powdery mildew of cucumber iscompletely combatted by the application of a fungicidal compositioncontaining 400 ppm. of a compound of generic formula I.

It has also been found that these novel fluoroalkoxyphenyl-substitutednitrogen heterocycles are especially effective in inhibiting internodalgrowth of plants when applied at rates within the range of about 0.125to about 5 lbs./A. At these rates, there is no adverse effect or injuryto the plants. Larger amounts can be used, but are not economicallyattractive. The exact amount of compound to be used will vary somewhatdepending upon the activity of the particular compound being used andthe sensitivity of the particular plant being treated.

The types of plants that have been found to be affected in this mannerby these compounds include crop plants, ornamental plants, woody plantsand turf. Specific examples of these types of plants include cucumber,soybean, chrysanthemum, wheat, oats, barley, corn, rye, flax, privet,rice, cotton, tomato and bluegrass.

While there is no wish to be bound to any theory as to the mode ofactivity of these compounds, it is believed that the compounds owe theiractivity to their unique properties as gibberellic acid antagonists.This would explain the broad spectrum activity of the compounds. Inex-plant assays designed to demonstrate gibberellic acid activity, thecompounds have performed as antagonists at levels as low as about 10⁻ ⁵M. Further, when both the inhibiting compound and gibberellic acid areapplied to plants at the same time, growth-inhibiting effects arepartially neutralized. The growth of inhibited plants is stimulated whengibberellic acid is applied anytime after application of the inhibitor.

It has been observed that root applications of these compounds haveresulted in the greatest activity. However, other methods ofapplication, such as foliar spray or seed treatment can be used withsome degree of success. For application, the compounds are formulatedinto drenches, spray concentrates, wettable powders, dusts, etc., inaccordance with procedures known in the art.

For any such uses, the compounds are formulated into compositionsdesirably containing, in addition to the fluoroalkoxyphenyl-substitutednitrogen heterocycle, one or more of a plurality ofagriculturally-acceptable additaments, including water, polyhydroxycompounds, petroleum distillates, and other dispersion media,surface-active dispersing agents, emulsifiers, and finely-divided inertsolids. The concentration of the particularfluoroalkoxyphenyl-substituted compound in these compositions may varydepending on whether the composition is intended as an emulsifiableconcentrate or a wettable powder designed to be subsequently dilutedwith additional inert carrier, such as water, to produce the ultimatetreating composition, or is intended for direct application as a dust toplants.

Thus, treating compositions are most conveniently formulated bypreparing liquid or solid concentrates, which are subsequently dilutedto the desired level for use.

Emulsifiable liquid concentrates can be prepared by incorporating fromabout 4.5 to about 24 percent by weight of the active ingredient and anemulsifying agent in a suitable water-immiscible organic liquid. Suchconcentrates may be further diluted with water to form spray mixtures inthe form of oil-in-water emulsions. Such spray compositions thencomprise active toxicant, water-immiscible solvent, emulsifying agent,and water. Suitable emulsifying agents can be of the nonionic or ionictypes, or blends thereof, and include condensation products of alkyleneoxides with phenols and organic acids, polyoxyethylene derivatives ofsorbitan esters, complex ether-alcohols, ionics of the aralkyl sulfonatetype, and the like. Suitable water-immiscible organic liquids to beemployed include aromatic hydrocarbons, aliphatic hydrocarbons,cycloaliphatic hydrocarbons, and mixtures thereof such as petroleumdistillates.

Solid concentrate mixtures can be prepared by incorporating from about10 to about 50 percent by weight of the fluoroalkoxyphenyl-substitutednitrogen-heterocycle compound in a finely-divided inert solid carriersuch as bentonite, fuller's earth, diatomaceous earth, hydrated silica,diatomaceous silica, expanded mica, talc, chalk, and the like. Suchconcentrates can be formulated, if desired, for direct use as dustingcompositions, or can be diluted, if desired, with additional inert solidcarriers to produce dusting powders containing around 0.05 to 1 percentby weight of the fluoroalkoxyphenyl-substituted compound. Alternatively,surfactants, that is, dispersing and/or wetting agents, can beincorporated along with the fluoroalkoxyphenyl-substituted compound inthe solid carrier to form wettable powder concentrates ranging from 10to 25 percent by weight concentration, which subsequently can bedispersed in water or other hydroxylated carrier to form spraycompositions. Suitable surfactants include condensed aryl sulfonic acidsand sodium salts thereof, sodium lignosulfate, sulfonate-oxidecondensate blends, alkyl aryl polyether alcohols, sulfonate/nonionicblend, anionic wetting agents, and the like.

Further, the fluoroalkoxyphenyl-substituted nitrogen heterocyclecompound can be incorporated in solutions, simple dispersions, aerosolformulations, and other media adaptable to be employed for treatingvegetation or applying to the soil.

The rate of application of these novel compounds will vary with theparticular compound being employed and the plant being treated. Ingeneral, the compound should be applied at a rate within the range ofabout 0.125 to about 5 pounds per acre, and preferably within the rangeof about 0.125 to about 2 pounds per acre. As discussed above, the modeof application also affects the degree of activity and could result indifferences in the effective amount. The preferred method of applicationof the instant novel compounds is as a soil drench. Not surprisingly, ithas been found that mature plants are not as susceptible as immatureones.

The following experiment will illustrate the growthinhibiting activityof these novel compounds.

EXPERIMENT

The growth regulator activity of a number of representative compoundscoming within the scope of the generic formula, supra, was tested in thefollowing manner.

Plant growth regulator compositions were prepared by dissolving 62.5 mg.of test compound in 1 ml. of acetone:ethanol (1:1 by volume) and adding24 ml. of an aqueous mixture of a sulfonate emulsifier and a nonionicemulsifier, to give a final volume of 25 ml., with a test compoundconcentration of 2500 ppm. This composition was then serially diluted bya factor of 5, with the aqueousemulsifier mixture, to give 500 and 100ppm. solutions.

Foliar sprays were applied with a DeVilbiss atomizer operated at 10 to12 psi. Soil drenches were poured into the pot as rapidly as possiblewithout overflowing.

Soybeans, variety Amsoy, were planted in 4-inch square plastic pots andthinned to one plant per pot shortly after emergence. Bluegrass, varietyKentucky, was planted in 3-inch square plastic pots in sterile soil.Chrysanthemums, variety Princess Ann, purchased as rooted cuttings ofgenetically pure stock, were transplanted upon receipt into 4-inchsquare plastic pots. Standard greenhouse soil (1/2 Brookston silty loamand 1/2 coarse sand by volume) was used.

Treatments were applied after the chrysanthemums had been established inthe pots for about 8 to 15 days; after the soybeans had reached 9 to 11days of age, when the first trifoliate had fully expanded; and after thebluegrass was 20 to 30 days old.

Fertilizer applications were made weekly using a hose-end proportionerto apply 6.7 g./gallon of 23-19-17 Rapid-Gro soluble fertilizer duringroutine hand watering.

A reference standard,α-cyclopropyl-α-(4-methoxyphenyl)-5-pyrimidinemethanol, was used, and itwas formulated and applied in the same manner and rates as the testcompounds. Six or more untreated plants of each species were included ascontrols.

Bluegrass was clipped to a height of one-half inch one day beforetreatment and again approximately one week after treatment.

Observations were made on bluegrass and chrysanthemums 25 days aftertreatment, and on soybeans 15 to 25 days after treatment, depending ongrowing conditions (during cloudy weather, soybeans eliolate and must beread out early).

The test chemicals, formulated as described above, were applied to Amsoysoybeans, Princess Ann chrysanthemums, and Kentucky bluegrass, by bothfoliar spray and soil drench, at three rates for each mode ofapplication. Duplicate sets of untreated controls were employed. Thegrowth of the treated plants was compared to the controls and the degreeof inhibition noted by a numbering system having the following meaning:

+3 = Distinct promotion

+2 = Moderate promotion

+1 = Slight promotion

0 = No effect

-1 = Slight inhibition

-2 = Moderate inhibition

-3 = Severe inhibition

The average results from the two sets of plants treated with each of thetest compounds are reported in the following charts. Chart 1 sets forththe results of the soil drench treatment, and Chart 2 the results of thefoliar spray treatment. In both charts, column 1 lists the testcompounds, column 2, the application rate in pounds per acre (Chart 1),and parts per million (ppm., Chart 2); columns 3, 4, and 5, list thetest plants and the degree of growth inhibition observed.

                  CHART 1                                                         ______________________________________                                                        Drench                                                                     Rate     Soy-     Blue-                                          Compound     lb./A.   bean     grass  Mum                                     ______________________________________                                        α-Isopropyl-α-                                                                 0.4      0        -1     0                                       [p-(trifluoro-                                                                             2.0      0        -2     0                                       methoxy)phenyl]-                                                                           10.0     -1.5     -3     -2.5                                    5-pyrimidinemethanol                                                          α-Isopropyl-α-                                                                 0.4      -2       -2     0                                       [p-(1,1,2,2- 2.0      -3       -3     -1                                      tetrafluoro- 10.0     -3       -3     -2                                      ethoxy)phenyl]-                                                               2-pyrazinemethanol                                                            α-Isopropyl-α-                                                                 0.4      0        -1     0                                       [p-trifluoro-                                                                              2.0      -1       -2     -1                                      methoxy)phenyl]-                                                                           10.0     -1       -3     -3                                      2-pyrazinemethanol                                                            α-Isopropyl-α                                                                  0.4      -2       -1     -1                                      [p-(pentafluoro-                                                                           2.0      -2       -2     -2                                      ethoxy)phenyl]-                                                                            10.0     -3       -3     -3                                      5-pyrimidine-                                                                 methanol                                                                      α-n-Propyl-α-                                                                  0.4      -2       0      -1                                      [p-(trifluoro-                                                                             2.0      -1       -1     -2                                      methoxy)phenyl]-                                                                           10.0     -2       -3     -3                                      5-pyrimidine-                                                                 methanol                                                                      α-Phenyl-α-                                                                    0.4      0        0      0                                       [p-(1,1,2,2- 2.0      -2       0      0                                       tetrafluoro- 10.0     -3       -3     -1                                      ethoxy)phenyl]-                                                               5-pyridinemethanol                                                            α-Isopropyl-α-                                                                 0.4      -2       -1     -1.5                                    [p-(trifluoro-                                                                             2.0      -2       -2.5   -2                                      methoxy)phenyl]-                                                                           10.0     -3       -3     -2                                      5-pyrimidine-                                                                 methanol                                                                      α-Isopropyl-α-                                                                 0.4      -2       0      -2                                      [p-(1,1,2,2- 2.0      -3       -1     -3                                      tetrafluoro- 10.0     -3       -3     -3                                      ethoxy)phenyl]-                                                               5-pyrimidine-                                                                 methanol                                                                      α-[3,4-(Difluoro-                                                                    0.4      -2       0      -1                                      methylenedioxy)-                                                                           2.0      -2       -2     -2                                      phenyl]-α-iso-                                                                       10.0     -2       -3     -2                                      propyl-5-pyrimi-                                                              dinemethanol                                                                  α-[3,4-(Difluoro-                                                                    0.4      0        0      0                                       methylenedioxy)-                                                                           2.0      0        0      0                                       phenyl]-α-undecyl-                                                                   10.0     0        0      -1                                      5-pyrimidine-                                                                 methanol                                                                      α-Cyclohexyl-α-                                                                0.4      0        0      0                                       [3,4-(difluoro-                                                                            2.0      -2       0      0                                       methylenedioxy)-                                                                           10.0     0        -3     0                                       phenyl]-5-pyrimi-                                                             dinemethanol                                                                  α-Cyclohexyl-α-                                                                0.4      0        0      0                                       [p-(1,1,2,2- 2.0      0        -3     0                                       tetrafluoro- 10.0     0        -3     -3                                      ethoxy)phenyl]-                                                               5-pyrimidine-                                                                 methanol                                                                      α(n-Hexyl)-α-[p-                                                               0.4      0        0      0                                       (1,1,2,2-tetra-                                                                            2.0      0        0      0                                       fluoroethoxy)-                                                                             10.0     0        -2     0                                       phenyl]-5-pyrim-                                                              idinemethanol                                                                  Controls    0        0        0      0                                       ______________________________________                                    

                  CHART 2                                                         ______________________________________                                                        Spray                                                                      Rate     soy-     Blue-                                          Compound     ppm.     bean     grass  Mum                                     ______________________________________                                        α-Isopropyl-α-                                                                 100      0        0      -1.5                                    [p-(trifluoro-                                                                             500      -1       -1.5   -2                                      methoxy)phenyl]-                                                                           2500     -1       -3     -3                                      3-pyridine-                                                                   methanol                                                                      α-Isopropyl-α-                                                                 100      -2       0      -1                                      [p-(1,1,2,2- 500      -3       -3     -3                                      tetrafluoro- 2500     -3       -3     -3                                      ethoxy)phenyl]-                                                               2-pyrazine-                                                                   methanol                                                                      α-Isopropyl-α-                                                                 100      0        -1     -1                                      [-p(trifluoro-                                                                             500      -1       -2     -2                                      methoxy)phenyl]-                                                                           2500     -2       -3     -2                                      2-pyrazine-                                                                   methanol                                                                      α-Isopropyl-α-                                                                 100      -2       0      -2                                      [p-(pentafluoro-                                                                           500      -3       -2     -3                                      ethoxy)phenyl]-                                                                            2500     -3       -3     -3                                      5-pyrimidine-                                                                 methanol                                                                      α-n-Propyl-α-                                                                  100      -1       0      -2                                      [p-trifluoro-                                                                              500      -3       0      -2                                      methoxy)phenyl]-                                                                           2500     -3       -2     -3                                      5-pyrimidine-                                                                 methanol                                                                      α-Phenyl-α-[p-                                                                 100      0        0      0                                       (1,1,2,2-tetra-                                                                            500      -1       0      0                                       fluoroethoxy)-                                                                             2500     -3       0      0                                       phenyl]-5-                                                                    pyrimidine-                                                                   methanol                                                                      α-Isopropyl-α-                                                                 100      -2       -1     -2                                      [p-(trifluoro-                                                                             500      -2.5     -2     -2                                      methoxy)phenyl]-                                                                           2500     -2.5     -2.5   -2.5                                    5-pyrimidine-                                                                 methanol                                                                      α-Isopropyl-α-                                                                 100      -1       0      -2                                      [p-(1,1,2,2- 500      -2       -1     -3                                      tetrafluoro- 2500     -3       -3     -3                                      ethoxy)phenyl]-                                                               5-pyrimidine-                                                                 methanol                                                                      α-[3,4-(Difluoro-                                                                    100      0        0      0                                       methylenedioxy)-                                                                           500      0        -1     -1                                      phenyl]-α-isopro-                                                                    2500     -2       -3     -1                                      pyl-5-pyrimidine-                                                             methanol                                                                      α-Cyclohexyl-α-                                                                100      0        -1     -1                                      [p-(1,1,2,2- 500      0        -2     0                                       tetrafluoro- 2500     0        -3     -3                                      ethoxy)phenyl]-                                                               5-pyrimidine-                                                                 methanol                                                                      Controls     0        0        0      0                                       ______________________________________                                    

It is not unexpected that the activity of these compounds as plantgrowth regulators varies depending on the plants treated and the methodused for applying the growth regulating composition, whether by spray,or by drench, and further, that not every compound is active by everymethod of application.

We claim:
 1. A method of inhibiting the internodal growth of plantswhich comprises contacting the plants selected from the group consistingof crop plants, ornamental plants, and turf, with an effective growthinhibiting amount of a compound of the formula ##EQU3## wherein R is5-pyrimidinyl;R¹ is isopropyl; R² is trifluoromethoxyphenyl,tetrafluoroethoxyphenyl or pentafluoroethoxyphenyl; X is hydroxy; andthe nonphytotoxic acid addition salts thereof.
 2. The method of claim 1wherein the compound is applied at the rate of from about 0.125 to about5 lbs. per acre.
 3. The method of claim 1 wherein the compound isapplied at the rate of from about 0.125 to about 2 lbs. per acre.
 4. Themethod of claim 1 wherein the active compound isα-isopropyl-α-[p-(trifluoromethoxy)phenyl]-5-pyrimidinemethanol.
 5. Themethod of claim 1 wherein the active compound isα-isopropyl-α-[p-(pentafluoroethoxy)phenyl]-5-pyrimidinemethanol.
 6. Themethod of claim 1 wherein the active compound isα-[3,4-(difluoromethylenedioxy)phenyl]-α-isopropyl-5-pyrimidinemethanol.7. The method of claim 1 wherein the growth-inhibiting compound is usedin the form of a composition comprising an effective amount of acompound of the formula ##EQU4## wherein R is 5-pyrimidinyl;R¹ isisopropyl; R² is trifluoromethoxyphenyl, tetrafluoroethoxyphenyl, orpentafluoroethoxyphenyl; X is hydroxy; and the nonphytotoxic acidaddition salts thereof, an agriculturally-acceptable inert carrier, anda dispersing agent.
 8. A growth-inhibiting composition comprising aneffective growth-inhibiting amount of a compound of the formula ##EQU5##wherein R is 5-pyrimidinyl;R¹ is isopropyl; R² istrifluoromethoxyphenyl, tetrafluoroethoxyphenyl, orpentafluoroethoxyphenyl; X is hydroxy; and the nonphytotoxic acidaddition salts thereof, an agriculturally-acceptable inert carrier, anda dispersing agent.
 9. A composition as defined in claim 8 wherein thecompound isα-isopropyl-α[p-(trifluoromethoxy)phenyl]-5-pyrimidinemethanol